An excess of airborne flammable dust or deposited flammable dust in closed spaces can pose an explosion hazard. This is the case for some underground mining operations, and especially so for underground coal mining. As coal is extracted from its surroundings, the process inevitably produces coal dust. The coal dust deposits onto surfaces of the mine and collects, and the deposited coal dust creates a highly flammable and explosive situation. If a spark from equipment, or other ignition source, is introduced to a deposit of coal dust, a fire or explosion may be ignited.
One of the techniques for preventing explosions in mines is dispersing a mixture of inflammable rock dust or a mixture of water and inflammable rock dust. The rock dust mixture coats the ceilings, floors, and pillars in the mine, creating a sealing layer of inflammable material over the highly flammable coal dust which is deposited there. This is an established technique which is required and regulated by safety regulations. Special attention is paid to surface areas near a coal face currently being worked. Typically, equipment dedicated to dispersing the flame prevention mixture is used. This requires moving additional equipment into the work area and may even require moving mining equipment out of the way to make room for the dispersing equipment in tight spaces.